CAMPAIGNERS have warned that the South Downs National Park (SDNP) could be surrounded by fracking rigs if the Government lets energy companies drill underneath it.

Directors from the RSPB, the Campaign to Protect Rural England, the National Trust and The Wildlife Trusts England have joined together in urging energy secretary Amber Rudd, who is also MP for Hastings and Rye, to rethink the idea.

Ministers previously agreed to a ban on fracking in protected areas such as the SDNP and Areas of Outstanding Natural Beauty but are this week expected to outline laws allowing the controversial practice to tunnel underneath them.

The condition is that drilling rigs are situated just outside the boundaries.

Fracking generally involves drilling more than a mile down into the ground and then out horizontally, potentially more than a mile and a half, allowing companies to access shale gas under national parks without touching the surface.

The directors, along with fishing groups, said drilling rigs even outside the boundaries of sensitive sites such as the SDNP would “harm their tranquillity and people’s enjoyment of them” in a letter to a national newspaper.

They wrote: “While we welcome the Government’s previous commitment to rule out fracking in particularly sensitive areas, we believe drilling beneath these areas should also be explicitly ruled out.

“While the wells may be just outside protected areas, pollution - and visual, noise and light disturbance - won’t respect those boundaries.”

Ministers first introduced restrictions on fracking in national parks last summer, with guidance saying it could only take place “in exceptional circumstances”, following a campaign calling for frack-free zones.

Under pressure from some MPs in January, the Government went further by agreeing to introduce an outright ban on fracking “within or under” protected areas.

Less than a month later, however Ms Rudd, claimed a ban on fracking beneath national parks would “not be sensible” because it could “unduly constrain” the industry.

She said: “For example, in the case of areas of outstanding natural beauty and national parks, given their size and dispersion, it might not be practical to guarantee that fracking will not take place under them in all cases without unduly constraining the industry.”

The precise details of what will be allowed are expected to be put before Parliament in secondary legislation this week.